Automatic air injector system



Aug. 30, 1966 TEl-FORD ET 3,269,318

AUTOMATIC AIR INJECTOR SYSTEM Filed April 10, 1964 INVENTORS 0mm 0. rzLFo/eo BY cm/ewcz L. Perm/m0 Arron/wa s United States Patent 3,269,318 AUTOMATIC AIR INJEUTOR SYSTEM Carlyle 0. Telford, Hayward, and Clarence lL. Pritchard,

Castro Valley, Calif assignors to Malsbary Manufactnring Company, (Balrland, Caiifi, a corporation of California Filed Apr. 10, 1964, Ser. No. 358,764 6 Claims. (Cl. 103-6) The present invention relates to improvements in an automatic air injector system, and particularly to an automatic air injector system for recharging the cushion of air in a pressure chamber containing air and liquid under pressure.

It is well known to provide accumulator tanks or pressure chambers in systems which supply liquid under pressure in order to provide a constant supply of liquid at the required pressure. It is also well known to use pressure chambers with a cushion of air at the upper portion thereof, in order to dampen :any variations between the supply of fluid from the pressurized inlet line as fluid is pumped therethrough and to eliminate water hammer. However, certain liquids such as hot water tend to absorb air from this pressure chamber or dome, and even where the solubility is rather low, as in the case of water, the air cushion is soon depleted when a heavy flow of liquid is provided under high pressure.

Various systems have been provided to add air in order to replace the air depleted as indicated above, and these systems have generally improved upon the problem. However, certain of the prior systems have the disadvantage of not being capable of performing under all demand or load conditions likely to be given to a device of this nature, particularly in a high pressure system. Alternatively, prior systems required extensive structure in order to give satisfactory performance. It has been particularly diflicult to provide a satisfactory system where relatively high pressures are impressed on the liquid.

It is therefore a primary object of the present invention to provide a liquid supply system containing an air injector for replacing lost air to an air cushion under pressure in a tank having a pressure dome.

Another object of the invention is to provide a liquid pressure system utilizing an air injector of the character described which is constructed to be responsive to the amount of liquid supplied through the tank.

A further object of the invention is to provide a liquid pressure system containing an air injector of the character described which is capable of pumping air from the atmosphere and delivering it to a pressure tank under a relatively high pressure.

Still another object of the invention is to provide a water pressure system in which air is charged into the pressure tank together with water which serves to positively assure a charging of air over a comparatively high pressure differential.

Further objects and advantages of the invention will be apparent as the specification progresses, and the new and useful features of the automatic air injector system will be fully defined in the claims attached hereto.

The preferred form of the invention is illustrated in the accompanying drawings, forming a part of this description, in which:

FIGURE 1 is a schematic elevational view illustrating a typical system incorporating a preferred embodiment of the present invention;

FIGURE 2, an enlarged sectional view of the air injector assembly of FIGURE 1 illustrating in detail the internal structure thereof; and

FIGURE 3, a sectional view similar to FIGURE 2 illustrating the air injector assembly, but in another operative position to better illustrate the mode of operation of the present invention.

Patented August 30, 1966 While only the preferred form of the invention is shown, it should be understood that various changes or modifications may be made within the scope of the claims attached hereto without departing from the spirit of the invention.

Referring to the drawing in greater detail, there is shown a typical water pressure system 11 containing a tank 12 providing a chamber to hold water 13 and an air cushion 14 in the upper portion 16 or dome of the tank. The system also contains a main supply line 17, a main supply pump 18 in line 17 and an output line 19 from the tank. So far, the system is more or less conventional and the present invention relates to the use of an air injector assembly 21 located in a branch line 22 in the system.

In the preferred form of the invention, the pump 18 should be of the pulsating type which has a reciprocating member driven by motor 23 soas to produce pulses on the output side of the pump in lines 17 and 22. The branch line 22 may be located on the output side of the pump as shown or anywhere in line 17 where it might receive the pulses of the pump so that these pulses may be transmitted through a liquid coupling therein to operate the air injector assembly 21. The output of branch line 22 is line 24 from the air injector 21 and this line may terminate anywhere in tank 12 capable of delivering air to the upper portion thereof, the air injector 21 serving to supply a small quantity of water and air to the tank during the operation of the pump 18.

It is important that the air injector receive pulses, and any means for providing them will be suitable. However, it is desirable to have the pulses dependent on the liquid flow through the system as in the case of a pulsating pump.

As best seen in FIGURES 2 and 3, the air injector assembly 21 comprises a reciprocating member such as the diaphragm 26 serving as a slave pump operated by the pulses in the fluid line 22, the diaphragm being in communication therewith through ports 27. The reciprocating diaphragm also provides pulsating pressures in an air supply chamber 28 on the far side thereof through ports 29. The air chamber 23 is in communication with the tank through outlet line 24, but a spring loaded oneway check valve 31 prevents reverse movement of material from the tank or loss of pressure therein. Air is supplied to the air supply chamber 28 through an air inlet line 32 which is open to the atmosphere and contains an air check valve 33 therein having a circle seal and little resistance to entry of air into the chamber. However, the check valve 33 prevents movement of air or water outward from air supply chamber 28 when the supply chamber is under pressure.

An important feature of the air injector of this invention is the liquid supply by-pass 34 provided around the slave pump through which water passes during the pulsating operation to provide small amounts of water into air supply chamber 28. This liquid supply by-pass 34 is equipped with a spring loaded one-way check valve 36 to prevent reverse flow therethrough and an orifice 37 for controlling and restricting the amount of water passing through the by-pass. Although the flow of water is restricted, it is seen that some water goes through this by-pass on every stroke.

As here shown, the air injector assembly 21 is preferably constructed in two halves which are bolted together by means of bolts 38 so as to allow easy access to the diaphragm and the orifice for servicing thereof. In addition, the one-way check valves 31 and 36 are carried in conventional valve seats and may be reached through threaded fittings 39. This access is important not only for servicing, but to allow the springs to be changed to adjust the spring pressure on the valve. The regulation of the spring pressure, particularly the spring pressure of check valve 31, is an important factor in determining the amount of air being pumped into the tank by the air injector.

The operation of the device is described below to better illustrate that at the beginning of the operation, the air injector 21 has no water in its air chamber 28 and the injector will not operate with a high pressure system until water fills the chamber. This illustrates the importance of the by-pass. However, when the pump 18 is turned on, Water soon fills the fluid coupling 22 and the water side of the air injector 21 and begins to pass through by-pass 34.

With the fluid coupling established, the diaphragm 26 reciprocates together with the main pump in pulsating manner between extreme positions such as those shown in FIGURES 2 and 3. As the diaphragm is retracted to the position shown in FIGURE 2, air is drawn into the air chamber 28 through air inlet line 32. Then when the diaphragm moves to the extreme right position as shown in FIGURE 3, the air compresses in the air supply chamber 28, and provides pressure against the check valve 31 and thereby tends to enter the tank 12. However, it will be appreciated that the amount of pressure built up in air supply chamber 28 will be limited by difierence in volume of the air caused by the displacement of the diaphragm in accordance with Boyles law.

Accordingly, with the set-up 'here shown, air will be supplied to the tank when air supply chamber 28 is full of air only if relatively low pressures are present in the tank. However, it is desired to supply air to the pressure tank at relatively high pressures such as say 400 pounds per square inch. If We assume about a two pound per square inch pressure drop through the inlet line 32 from the atmosphere, the absolute air pressure at the end of the suction stroke of the diaphragm in chamber 28 will be say 13 pounds per square inch. Accordingly, the air volume would have to be compressed to an amount greater than of its original volume to provide the necessary output pressure. In order to build a supply chamber 28 small enough to provide the necessary ratios, it is seen that the construction problems would be virtually impossible to overcome in order to take in and deliver enough air. However, by filling the chamber with water which enters through by-pass line 34, the water tends to assist in aiding the diaphragm to provides the necessary pressure on the air to provide pumping movement of the air.

Thus, on the pressure pulse in line 22, a small amount of water passes through the check valve 36, and through orifice 37 to squirt into the air supply chamber 28. The air in this chamber tends to rise to the top of the Water and soon the water in the chamber is suflicient to build up enough pressure so that air and water are ejected through check valve 31 and into the accumulator tank. The air injector then continues in normal operation with the liquid levels varying somewhat as shown in FIG- URES 2 and 3. Thus, on the back stroke as shown in FIGURE 2, air bubbles in through the water into the upper portion of chamber 28 and pressure in the chamber will be of the order of say about 13 p.s.i.a. When the diaphragm is pushed to the right as shown in FIG- URE 3, the pressure in chamber 28 builds up to an amount of say in excess of 400 p.s.i.g. with a result that the air bubbles virtually disappear and a charge of air and water is forced through the check valve 31 and into the tank through line 24.

With this operation, it is seen that on each pulse of the main supply pump 18, a small amount of air is injected into the tank so that air which is lost from the tank will be replenished. It is also seen that this resupply is dependent on the operation of the pump, which in turn is related to the loss of air from the tank through solution in the hot water under pressure.

For example, in a typical operation, an accumulator tank or dome of six inch diameter was operated without injecting air through the air injector. It was observed through a sight glass that the loss of air was so rapid that the water in the dome rose at the rate of approximately /2 in. per hour. Obviously, such rapid loss of air cannot be tolerated. On the other hand, using the air injector assembly of this invention under the same conditions, the system has been operated under test conditions for two months and a full supply of air was still present in the pressure dome.

From the foregoing description, it is seen that we have provided an automatic air injector system suitable for supplying air to an air pressure dome in a liquid system which is simple in construction and absolutely reliable in operat1on.

We claim:

1. In a water pressure system containing a tank having a pressure chamber designed to hold water in the lower portion thereof and an air cushion under pressure in the upper portion thereof, a main supply line to the tank, a pulsating main supply pump in said main supply line, and an output line in communication with the lower portion of said tank, in combination, an air injector comprising an air supply chamber in fluid communication with said tank, an air supply pump for pumping air from the atmosphere into said air supply chamber, water coupling means between the main supply pump and the air supply pump, and a water supply line connecting said water coupling means to said air supply chamber for delivering water to said air supply chamber in response to operation of said main supply pump, said air supply pump being operated in response to operation of said main supply pump for pumpmg air into said air supply chamber into water de livered thereto through said Water supply line, and for injecting air above the water level in said air supply chamber into the tank, the amount of air pumped into said air supply chamber and injected into said tank being responsive to the amount of water pumped to the tank by said main supply pump.

2. In a water pressure system containing a tank having a pressure chamber designed to hold water in. the lower portion thereof and an air cushion under pressure in the upper portion thereof, a main supply line to the tank, a pulsating main supply pump in said main supply line, and an output line in communication with the lower portion of said tank, in combination, an air injector comprising an air supply chamber in fluid communication with said tank, a one-way check valve between said air supply chamber and said tank positioned to allow fluid movement toward the tank but positioned for preventing reverse fiuid movement from the tank, an inlet line communicating between the air supply chamber and the atmosphere having a one-way check valve therein to prevent the flow of fluid from the chamber toward the atmosphere, an air supply pump for pumping air from the atmosphere mto said air supply chamber and from said air supply chamber into said tank, water coupling means between the main supply pump and the air supply pump, and a water supply line connecting said water coupling means to said air supply chamber for delivering water to said air supply chamber in response to operation of said main supply pump, said air supply pump being operated in response to operation of said main supply pump for pumprng air mto said air supply chamber into water delivered thereto through said water supply line, and for injecting air above the water level in said air supply chamber into the tank, the amount of air pumped into said air supply chamber and injected into said tank being responsive to the amount of Water pumped to the tank by said main supply pump.

3. In a water pressure system containing a tank having a pressure chamber designed to hold water in the lower portion thereof and an air cushion under pressure in the upper portion thereof, a main supply line to the tank, a pulsating main supply pump in said main supply line, and an output line in communication with the lower portion of said tank, in combination, a branch line leading from the pulsating main supply pump to the tank and an air injector in said branch line, said air injector comprising an air supply chamber in fluid communication with said tank, an air supply pump for pumping air from the atmosphere into said air supply chamber, a water by-pass line around the air supply pump extending from the branch line in front of the air supply pump to the air supply chamber for delivering Water from said branch line to said air supply chamber in response to operation of said main supply pump, and means for restricting the flow of water in said by-pass line, said air supply pump being operated in response to operation of said main supply pump for pumping air into said air supply chamber into water delivered thereto through said water by-pass line, and for injecting air above the water level in said air supply chamber into said tank, the amount of air pumped into said air supply chamber and injected into said tank being responsive to the amount of water pumped to said tank by said main supply pump.

4. In a water pressure system containing a tank having a pressure chamber designed to hold water in the lower portion thereof and an air cushion under pressure in the upper portion thereof, a main supply line to the tank, a pulsating main supply pump in said main supply line, and an output line in communication with the lower portion of said tank, in combination, a branch line leading from the pulsating main supply pump to the tank and an air injector in said branch line, said air injector comprising an air supply pump for pumping air from the atmosphere into said air supply chamber, a Water by-pass line around the air supply pump extending from the branch line in front of the air supply pump to the air supply. chamber for delivering water from said branch line to said air supply chamber in response to operation of said main supply pump, a one-way check valve in said by-pass line, and an orifice in said by-pass line, said air supply pump being operated in response to operation of said main supply pump for pumping air into said air supply chamber into water delivered thereto through said water by-pass line, and for injecting air above the water level in said air supply chamber into said tank, the amount of air pumped into said air supply chamber and injected into said tank being responsive to the amount of water pumped to said tank by said main supply pump.

5. In a water pressure system containing a tank having a pressure chamber designed to hold water in the lower portion thereof and an air cushion under pressure in the upper portion thereof, a main supply line to the tank, a pulsating main supply pump in said main supply line, and an output line in communication with the lower portion of said tank, in combination, a branch line leading from the pulsating main supply pump to the tank and an air injector in said branch line, said air injector comprising an air supply chamber in fluid communication with said tank, a one-way check valve between said air supply chamber and said tank positioned to allow fluid movement toward the tank but positioned for preventing reverse fluid movement from the tank, an inlet line communicating between the air supply chamber and the atmosphere having a oneway check valve therein to prevent the flow of fluid from the chamber toward the atmosphere, an air supply pump in said branch line in fluid coupling relation to the main supply pump, a water by-pass line around the air supply pump extending from the branch line in front of the pump to the air supply chamber for delivering water from said branch line to said air supply chamber in response to operation of said main supply pump, a one-way check valve in said by-pass line, and an orifice in said by-pass line, said air supply pump being operated in response to operation of said main supply pump for pumping air into said air supply chamber into water delivered thereto through said water by-pass line, and for injecting air above the water level in said air supply chamber into said tank, the amount of air pumped into said air supply chamber and injected into said tank being responsive to the amount of water pumped to said tank by said main supply pump.

6. In a water pressure system containing a tank having a pressure chamber designed to hold water in the lower portion thereof and an air cushion under pressure in the upper portion thereof, a main supply line to the tank, a main supply pump adapted to provide pulsations in said main supply line, and an output line in communication with the lower portion of said tank, in combination, an air injector comprising an air supply chamber in fluid communication with said tank, an air supply pump for pumping air from the atmosphere into said air supply chamber, water coupling means between the main supply pump and the air supply pump, and a water supply line connecting said water coupling means to said air supply chamber for delivering water to said air supply chamber in response to operation of said main supply pump, said air supply pump being operated in response to operation of said main supply pump for pumping air into said air supply chamber into water delivered thereto through said water supply line, and for injecting air above the water level in said air supply chamber into the tank, the amount of air pumped into said air supply chamber and injected into said tank being responsive to said pulsations in said main line.

References Cited by the Examiner UNITED STATES PATENTS 2,416,345 2/ 1947 Piccardo 103-6 2,435,053 1/1948 Piccardo 103-6 2,647,466 8/ 1953 Nash l036 2,708,881 5/1955 Carpenter 1036 3,171,351 3/1965 Shelter l036 FOREIGN PATENTS 860 1912 Great Britain. 39,235 2/1913 Sweden.

MARK NEWMAN, Primary Examiner.

SAMUEL LEVINE, Examiner.

W. L. FREEH, Assistant Examiner. 

1. IN A WATER PRESSURE SYSTEM CONTAINING A TANK HAVING A PRESSURE CHAMBER DESIGNED TO HOLD WATER IN THE LOWER PORTION THEREOF AND AN AIR CUSHION UNDER PRESSURE IN THE UPPER PORTION THEREOF, A MAIN SUPPLY LINE TO THE TANK, A PULSATING MAIN SUPPLY PUMP IN SAID MAIN SUPPLY LINE, AND AN OUTPUT LINE IN COMMUNICATION WITH THE LOWER PORTION OF SAID TANK, IN COMBINATION, AN AIR INJECTOR COMPRISING AN AIR SUPPLY CHAMBER IN FLUID COMMUNICATION WITH SAID TANK, AN AIR SUPPLY PUMP FOR PUMPING AIR FROM THE ATMOSPHERE INTO SAID AIR SUPPLY CHAMBER, WATER COUPLING MEANS BETWEEN THE MAIN SUPPLY PUMP AND THE AIR SUPPLY PUMP, AND A WATER SUPPLY LINE CONNECTING SAID WATER COUPLING MEANS TO SAID AIR SUPPLY CHAMBER FOR DELIVERING WATER TO SAID AIR SUPPLY CHAMBER IN RESPONSE TO OPERATION OF SAID MAIN SUPPLY PUMP, SAID AIR SUPPLY PUMP BEING OPERATED IN RESPONSE TO OPERATION OF SAID MAIN SUPPLY PUMP FOR PUMPING AIR INTO SAID AIR SUPPLY CHAMBER INTO WATER DELIVERED THERETO THROUGH SAID WATER SUPPLY LINE, AND FOR INJECTING AIR ABOVE THE WATER LEVEL IN SAID AIR SUPPLY CHAMBER INTO THE TANK, THE AMOUNT OF AIR PUMPED INTO SAID AIR SUPPLY CHAMBER AND INJECTED INTO SAID TANK BEING RESPONSIVE TO THE AMOUNT OF WATER PUMPED TO THE TANK BY SAID MAIN SUPPLY PUMP. 